METHOD OF PRODUCING HEAT-RESISTANT NANO-STRUCTURED CORROSION-RESISTANT NICKEL-BASED ALLOYS Russian patent published in 2017 - IPC C22C1/02 C22C1/06 C22C19/03 

FIELD: metallurgy.

SUBSTANCE: method includes melting of charge materials in vacuum, decarburizing refining of produced melt in two stages. At the first refining stage an oxidizing agent is introduced in amount exceeding the required amount for oxidation of carbon to its dioxide by 2.0-8.5 times, under inert gas atmosphere at pressure 20-150 mm hg, then the melt is deoxidized and the gas is removed, after which the second refining stage is carried out, where rare-earth metals are introduced in the amount exceeding more than 2.0-20.0 times the amount of carbon remaining in the melt after the first refining stage, after the second refining stage chromium with active alloying elements is added to the melt. After the first decarburization refining stage, a slag mixture is added to melt surface consisting of wt %: 35-65 BaO, 15-30 BaF₂, 15-30 BaCl₂, 5-15 NiO, in an amount of 0.3-0.8% of melt weight, in 2-3 stages with holding for 5-15 min after each additive, titanium is used as active alloying elements introduced into the melt with chromium, aluminium and at least one element selected from tantalum, carbon, niobium and hafnium. Stable results are obtained for the phosphorus content in the melt of less than 0.007 wt %.

EFFECT: increased durability of the alloys at operating temperatures.

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